Bridge.



No. 668,232; v Patented Feb. I9, 1901..

' J. B. STRAUSS.

BRIDGE.

(Application filed my 31, 1900.) (No Model.) -2 Sheets-Sheet l,

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JOSEPH B. STRAUSS, OF CHICAGO, ILLINOIS.

BRIDGE.

SPECIFICATION formingpart of Letters Patent No. 668,232, dated February19, 1901. Application filed May 31, 1900. Serial No. 18,643. (No model.)

To all whom it may concern:

Be it known that I, JOSEPH B. STRAUSS, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Bridges, of which thefollowing is a specification.

My invention relates to improvements in bridges, and has for its objectto provide a new and improved bridge of the kind which opens up so as toleave an unobstructed passageway for boats and the like.

My invention is illustrated in the accompanying drawings, wherein-Figure 1 is a View of a bridge embodying my invention. Fig. 2 is asection with parts omitted on line 2 2, Fig. 1. Fig. 3 is a section online 3 3, Fig. 1. Fig. 4 is a view showing a modified construction. Fig.5 is a section on line 5 5, Fig. 4. Fig. 6 is a view showing a furthermodification.

Like letters refer to like parts throughout the several figures.

One of the objects of my invention is to provide a lift-bridge whereinone part of the structure balances the other part either partially orwholly, thus reducing or eliminating the counterweights now used in allkinds of lift-bridges.

Another object of my invention is to arrange means for reducing theeffect of the counterweight for the main span without varying its armand in the same ratio that the arm of the main span decreases as it islifted to open the channel for boats.

A further object of my invention is to combine these two ideas and toalso provide a bridge having balancing trusses separate from the mainspan, so that they can be made separately and combined when placed inposition.

Referring now to the drawings,I have shown in Fig. 1 the main spans A,normally joined together at the center when the bridge is in anoperative position. I have shown only one half of the bridge in thisfigure, as the other half is an exact duplicate. The main span A ispivotally connected to the pier B. On each side of the main span is abalancingtruss O, which is also pivotally connected to the pier B, thebalancing-trusses being connected attheir outer ends to the main span A.

Each balancing-truss is provided with a rack O, engaged by a gear 0operated from a suitable motor in the operating-tower G Theapproach-span D is connected to the balancing-truss O at the point C bya rope or other flexible device. The rope D passes over suitable pulleyson the framework B and is connected to the end of the approach-spannearest the abutment B, the connection preferably being made to theI-bealn D The rope D passes over suitable pulleys and is connected tothe land end of the approachspan, as

shown, there being a suitable support D at the land end which supportsthe pulley D It will be understood that there are two ropes D and tworopes D one on each side of the approach-span. The approach-span isprovided with a suitable part or parts D which may be of any suitableconstruction, the only essential condition being that this part or theseparts, when there are more than one, are arranged so that they can passinto the water as the main span A lifts, thus displacing the water andgradually decreasing the effect of the approach-span as the arm of themain span decreases, due to its upward movement. The approach-span issupported by the ropes D and D, so that it acts either partially orwholly as a counterweight for the main span. This approach-span may besupported by placing blocks or the like under it when the bridge is inan operative position, if desired, the blocks being removed when it isdesired to open the bridge, so that the approach-span is free to movedownwardly as the main span is moved upwardly. In the drawings I haveshown four projecting parts D which work in suitable guides in theabutments, they being preferably provided with antifriction-rollers D.It will thus be seen that when it is desired to lift the bridge themotor in the tower O is started. The gear 0 is. then rotated, and by itsengagement with the rack it moves the outer end of the main span, andthe balancing-trusses swing upwardly. The approach-span then movesdownwardly, the parts D displacing more and more water the farther theapproachspan descends. The parts are so adjusted as to decrease theeffect of the approach-span in the proper proportion to make it have thedesired counterbalancing efiect.

In Fig. 4 I have shown a construction similar to Fig. 1, with theexception that the approach-span is omitted and the main span andbalancing-trusses are pivotally connected with suitable abutments at theshore. Suitable counterweights E are used, the counterweights beingconnected with the balancingtrusses O by the ropes E, as shown, saidropes passing over suitable pulleys on the support B. Thesecounterweights are confined within suit-able apartments E in theabutment, as shown in Fig. 5, so that they are gradually introduced orimmersed in the water as the main span rises. The apartments E areconnected with the water, so that they are partially filled with water,as shown. I prefer to connect these apartments with the river by meansof openings E as shown in Fig. 5,

sothat as the water is displaced by the counterweights it may be forcedout through these openings.

In Fig. 6 I have shown a construction similar to Fig. 1, with theexception that the ap proach-span D is connected with the main span A,so as to be a part thereof, projecting rearwardly from the pivotalpoint. This approach-span acts either partially or Wholly as acounterweight and moves downwardly as the main span moves upwardly. Asuitable opening is formed in the abutment to permit this, as indicated.In some instances, when the approach-span is short, it will be necessaryto add some counterweight, and this counterweight may be added in anydesired manner. The parts are so adjusted that the lever-arm of theapproach-span decreases proportionately with the lever-arm of the mainspan, so that a proper balancing effect is present in all positions. Thebalancingtrusses O are made separate from the main span and areconnected therewith when the parts of the bridge are in position. Whenthe bridge is in its operative position, the balancing-trusses engagethe shoes 0 so that they support the river end of the main span. Whenthe bridge is closed, the balancingtruss acts as an arch or cantaliverto carry a portion of the load of the main span to the abutment or pier.In opening the bridge the balancing-truss acts as an operating orlifting truss, and at the same time it transmits the action ofa suitablecounterweight in such manner as to balance the weight of the main spanas it rises and falls. This balancingtruss therefore acts as a support,as an operat-ing-truss, and as an equalizing-arm. This constructionproduces a lighter and cheaper superstructure, a smaller and cheaperpier and abutments, and a larger open channel'- way. This constructionalso lessens the ground needed for approaches and the machinerynecessary to operate the bridge and secures a bridge which lends itselfmore easily to esthetic designs.

The counterbalance, comprising a part which is introduced in a varyingdegree in the water or other liquid, is provided with is used and theconditions and circumstances presented. It is of course essential thatthe effect of the counterbalance and the arm of the main span varysimultaneously, so that the effect of the counterbalance will correspondwith the downward pull of the main span. The construction herein shownis a cheap, efficient, and economical construction by means of whichthis result may be obtained, and it is of course evident that thevarious parts may be arranged in many difierout ways. I have onlyattempted to illustrate a construction which would make my inventionclear.

In describing my device I have described a part which I have called themain span and have referred to the arm of this span. -Where I use theterm arm in this specification, I mean the moment-arm, and the term ishere used in the sense in which it is usually employed in engineeringconstruction.

' I claim- 1. A lift-bridge, comprising a main span to be lifted andlowered, a counterbalance there- 'for comprising a part movable withrelation to the main span and normally partially in- ,serted into thewater when the bridge is bejing operated, means for varying the portion50f said part inserted in the Water as'the position of the main span isvaried, so as to vary the effect of the counterbalance as the arm of themain span varies.

2. A lift-bridge, comprising a main span :and an approach-span, abalancing-truss connected with the main span and movably conjnected withthe approach-span, and means jfor moving said balancing-truss so as tolift ithe main span.

l- 3. A lift-bridge, comprising a main span and a shore end or part, amovable connection between the shore end and the main span, the parts soarranged that the shore end acts partially or wholly as a counterweightfor the :main span in all its various positions.

, 4. A lift-bridge, comprising a main span and a balancing-trussindependent of each other, so that they can be separately erected, thebalancing-truss adapted to be connected with the main span so as to actas a liftingarm.

5. A lift-bridge, comprising an approachspan, a main span and abalancing-truss, each independent and separate before the bridge {iserected, the several parts connected together when in position so thatone span acts to balance the other,either partially or wholly.

6. A lift-bridge, comprising a main span Y pivotally connected at oneend to a support, an approach-span also connected with said 1 support, abalancing-truss connecting the two spans, so that the approach-span actspartially or wholly as a counterweight for the ICC IIC

main span, and means for moving the balancing-truss so as to lift themain span.

7. A lift-bridge, comprising a main span pivotally connected at one endto a support, an approach-span also connected With said support, abalancing-truss connecting the two spans, so that the approach-span actspartially or wholly as a counterweight for the main span, an engagingdevice on said balancing-truss, a stationary part adapted to be engagedthereby, and means for moving said engaging device so that it willtravel along the stationary part.

8. A lift-bridge, comprising a main span adapted to be lifted, acounterweight therefor, and means for varying the effect of the conn-JOSEPH B. STRAUSS.

Witnesses:

DONALD M. CARTER, HOMER L. KRAFT.

